Final Portfolio for Spatial Analysis

Manasa Acharya

10/18/2021

INTRODUCTION

This portfolio has been created as a part of VIS 2128, a six-week module at the Harvard Graduate School of Design. The objective of this compilation to showcase the author’s skills in spatial mapping and analysis.The page displays a range of mapping functions through data of geographies spanning from Mumbai, India to Maui, Hawaii. Apart from the first map which was developed using ArcGIS, all other maps have been created using the R software. The sources of the point and polygon data in these maps include the respective city’s official open data portals, ESRI, and Open Street Maps.

MUMBAI: LAND EXPANSION

The following image has made use of a 1900 historic map retrieved from the Harvard Map Collection to show changing boundaries of Mumbai city across time.

Georeferenced Map

  • Skill: Georeferencing a historic map and adding layers of spatial data on the same

The map shows administrative boundaries of the Indian city that I belong to, Mumbai, pre (1814) and post colonialism (1968) against the backdrop of a map drawn by the British during the period of colonialism (1900). Mumbai was previously a set of small islands but over the years (and primarily during the British regime), it saw rapid expansion and land reclamation as can be seen in the historic map and polygon layers represented here.

SAN FRANCISCO: ACCESS TO TRANSIT

The following three maps display public transportation accessibility in the city of San Francisco, California.

Transit stops within walking distance

  • Skill: Calculating and displaying accessibility, based on travel time

The map below shows the number of transit stops that one can walk to within 10 minutes from any point in the map. It is apparent that the highest concentration of transit stops is in the north-eastern part of the city, with certain parts having access to more than 60 transit stops within a short walking distance.

Accessibility Score

  • Skill: Calculating and displaying accessibility, based on travel time
  • Skill: Converting between raster layers and vector layers
  • Skill: Displaying raster data on a map

This map leverages information from the previous one to create and display an accessibility score for different areas in the city on a raster map. The score is calculated based on a distance-decay function of the walking time to the nearest transit stop. It is an abstract and normalized means of communicating ease of access on a scale of 0 to 60.

Accessibility Score Polygons

  • Skill: Calculating and displaying accessibility, based on travel time
  • Skill: Converting between raster layers and vector layers
  • Skill: Displaying raster data on a map

The following map continues to build on the previous one by merging adjacent grid cells that have the same value to create polygons. This helps us group larger areas within the city based on ease of accessibility, which is helpful when one is planning at cross-neighborhood scales. As we can see from the nuances of the grids, there aren’t large parts of the city where adjacent areas have the exact same accessibility scores.

CHICAGO: SHOOTINGS AND POLICE STATIONS

The following two maps analyze issues of shootings and police stations in Chicago.

Incidence of Shootings

  • Skill: Displaying multiple vector layers on the same map
  • Skill: Aggregating point data to a layer of polygons

This map indicates the number of shootings in each Chicago neighborhood. A cursory glance at the map indicates a comparatively higher proportion of shootings along the central part of Chicago with lower numbers along the city borders.

Number of Police Stations

  • Skill: Displaying multiple vector layers on the same map
  • Skill: Aggregating point data to a layer of polygons

In this map, I attempt to investigate how many Chicago neighborhoods have police stations located in them. The code shows these neighborhoods in pink, and adds a summary of the total number of neighborhoods fulfilling this criteria.

MAUI: MULTIRACIAL POPULATION

This map shows the racial diversity of Maui citizens across different Census blocks.

  • Skill: Displaying data on an interactive map
  • Skill: Aggregating point data to a layer of polygons

On clicking the image below, you would be directed to an interactive map in a new tab. The map displays the percentage of population identifying with more than one race in different areas of Maui, as reported in the United States Decennial Census of 2010 . Hovering over the specific polygons will provide the reader with information about the Census block, while clicking it will allow them to read the total population and percentage of multiracial population in that block.